Why You Should Grow Marigolds With Tomatoes + 9 Other Companion Planting Tomato Combinations

When it comes to growing healthy, productive tomato plants, companion planting can be a game-changer. Some plants, like marigolds, can deter pests, improve soil quality, and enhance tomato growth, making them the perfect garden partners. In this guide, we'll explore why marigolds are a must-have companion for tomatoes and introduce nine other beneficial plants that will help your tomato plants thrive, fight off pests, and yield more fruit. Why You Should Grow Marigolds With Tomatoes 1. Marigolds Repel Tomato Pests Naturally One of the biggest reasons gardeners plant marigolds with tomatoes is their ability to repel common tomato pests, including: Aphids – These sap-sucking insects weaken tomato plants and attract ants. Whiteflies – Marigolds' scent repels whiteflies, which damage tomato leaves. Tomato Hornworms – These voracious caterpillars can strip a tomato plant overnight. Nematodes – Marigolds help kill root-knot nematodes that cause root damage. Pro Tip: French marigolds (Tagetes patula) are the best variety for deterring root-knot nematodes, while Mexican marigolds help repel aphids and whiteflies. 2. Marigolds Attract Beneficial Insects Marigolds attract pollinators like bees and butterflies, as well as predatory insects such as: Ladybugs – Natural predators of aphids and whiteflies. Lacewings – Their larvae feed on common tomato pests. Parasitic Wasps – These wasps help control caterpillar populations like hornworms. By planting marigolds near tomatoes, you're creating a natural pest control system in your garden! 3. Marigolds Improve Soil Health & Prevent Disease Marigolds have allelopathic properties, meaning they release natural chemicals into the soil that suppress harmful fungi and nematodes. Their deep roots help aerate the soil, reducing the risk of root diseases in tomatoes. When marigolds die, they enrich the soil with organic matter, improving soil quality for future crops. Pro Tip: For maximum effectiveness, plant marigolds in the same area for multiple growing seasons to reduce nematode populations over time. 4. Marigolds Enhance Tomato Growth & Flavor Believe it or not, marigolds can help improve the flavor and growth of tomatoes! Their root secretions enhance soil biodiversity, promoting healthier tomato roots. By keeping pests away, tomatoes suffer less stress, leading to better growth and higher yields. Some gardeners believe marigolds improve the flavor of tomatoes, though this is anecdotal. How to Plant Marigolds with Tomatoes Plant marigolds 6-12 inches away from tomato plants to avoid competition. Use French marigolds for best pest control. Avoid crowding—marigolds should get plenty of sunlight to thrive. 9 More Best Companion Plants for Tomatoes Besides marigolds, several other plants work exceptionally well with tomatoes. Here are 9 additional tomato companion plants that can boost yields, deter pests, and improve soil health. 1. Basil – Enhances Tomato Flavor & Repels Pests Basil repels mosquitoes, flies, and aphids. Some gardeners believe it enhances the flavor of tomatoes. Improves tomato plant health and reduces fungal diseases. Pro Tip: Plant basil close to tomatoes but not too close—they still need good airflow! 2. Garlic – A Natural Pest Repellent Deters aphids, spider mites, and caterpillars. Helps prevent fungal infections like powdery mildew. Can be planted between tomato rows as a natural barrier. Pro Tip: Harvest garlic after tomato season and use it in homemade pest sprays! 3. Carrots – Improve Soil Aeration & Save Space Carrots help loosen compacted soil, benefiting tomato roots. They grow well underneath tomato plants, saving space. Attract beneficial insects like hoverflies, which prey on aphids. Pro Tip: Thin out carrot seedlings to prevent overcrowding near tomato roots. 4. Nasturtiums – Trap Pests Away from Tomatoes Attract aphids away from tomatoes, acting as a “trap crop.” Deter whiteflies and beetles with their strong scent. Provide ground cover that helps retain soil moisture. Pro Tip: Plant nasturtiums along the edges of your tomato bed to draw pests away. 5. Peppers – A Symbiotic Relationship Tomatoes and peppers have similar growing requirements, making them easy to grow together. They don’t compete aggressively for nutrients. Growing them together reduces cross-contamination of pests. Pro Tip: Avoid overcrowding as both plants are heavy feeders and need space! 6. Lettuce – Provides Natural Shade Lettuce thrives in the shade of tomato plants, keeping the soil cooler. Suppresses weed growth around tomato plants. Doesn’t compete for nutrients since it has shallow roots. Pro Tip: Harvest lettuce before tomato plants grow too large and block sunlight completely. 7. Onions – Repel Pests & Improve Soil Deter aphids, slugs, and root maggots. Improve soil health by naturally repelling fungi. Can be planted as a border around tomato beds. Pro Tip: Harvest onions before tomato plants get too large to avoid competition. 8. Oregano – A Natural Pest Control Herb Repels harmful insects while attracting pollinators and beneficial predators. Releases aromatic oils that deter aphids and spider mites. Helps control fungal infections near tomato plants. Pro Tip: Let oregano flower to attract even more pollinators! 9. Borage – The Ultimate Pollinator Magnet Attracts bees, ladybugs, and predatory wasps. Repels tomato hornworms and cabbage worms. Improves tomato plant resilience by enriching the soil. Pro Tip: Borage is self-seeding—plant it once, and it will return every year! By incorporating marigolds and these nine other companion plants, you can create a thriving, pest-resistant, and highly productive tomato garden. Quick Recap – Best Tomato Companion Plants: Marigolds – Repel pests & improve soil health Basil – Enhances flavor & fights pests Garlic – Natural insect repellent Carrots – Loosens soil & saves space Nasturtiums – Attracts pests away Peppers – Grows well alongside tomatoes Lettuce – Provides shade & prevents weeds Onions – Repel insects & fungi Oregano – Deters pests & attracts pollinators Borage – Boosts pollination & prevents hornworms Which of these companion plants do you already grow? Let us know in the comments!